The present invention relates generally to analysis apparatus and more particularly to a mechanism for performing analysis of test tape having discrete test areas arranged adjacent each other along the length of the tape. The invention is particularly directed toward apparatus especially suited for the performance of urinalysis of samples contained on the test tape. The apparatus of the invention is of the type which utilizes a reflex photometer to determine the reflection capability of test areas on the tape in order to derive analytical data.
Urinalysis tapes are used as an aid in medical diagnosis. Such tapes contain test areas which visibly discolor when they are brought into contact with certain substances contained in the urine. In such urinalysis, a discoloration which corresponds to a pathological cencentration indicates a problem in an organ.
Each test tape contains several test areas which respond specifically to various substances in the urine. Since the chemical reactions in the test areas which cause discoloration to develop require the passage of a certain period of time, such discolorations develop only gradually. The developping coloring substances are frequently not stable and are altered under the influence of atmospheric oxygen or light. Therefore, the color and the depth of color of the test areas, which are a measure of the concentration of the substance to be analyzed, must be examined within a defined period of time after the test tape has been dipped into the urine sample. The evaluation of the concentration is frequently accomplished by a visual comparison utilizing color charts.
Since the human eye is not equally sensitive to all colors, the depth of color as a measure of the concentration of the substance is individually differently evaluated. By means of an analyzing apparatus for urinalysis tape known from German Offenlegungsschrift No. 25 57 872, it is possible to obtain analysis data which are independent of the individual conducting the analysis. This analyzing apparatus successively measures the reflection capability of individual test areas of a test tape by means of a reflex photometer. The reflex photometer has a measuring device with a light source which perpendicularly illuminates the test areas with monochromatic light and an integrating sphere or ball (Ulbricht's sphere) which receives the remitted light. In the integrating ball there is arranged adjacent the test area a photoelement for measuring light intensity in the integrating ball. The test tape to be analyzed lies in a receiving trough of a transport carriage which is moved by means of a drive motor in a longitudinal direction of the test tape beneath and past the measuring device of the reflex photometer.
To ensure clear results, the reflection capability must always be measured for a constant, predetermined period of time after the test tape has been dipped into the urine. To ensure this, the known analyzing apparatus contains a timer which is started at the time of dipping of the tape and which starts the movement of a carriage bearing the test tape only after a predetermined time period has elapsed. Since the carriage can only carry a single test tape, it is always necessary to await expiration of the entire predetermined time period before another test tape can be analyzed. The time period is usually in the order of magnitude of one minute. Accordingly, the known analyzing apparatus operates relatively slowly and is not particularly suited for performing a series of tests in which large amounts of test tapes must be analyzed.
The present invention is directed to the task of providing a simple analyzing apparatus for test tape, particularly urinalysis test tape, which can analyze the test tape automatically and which compared to known analyzing apparatus, can operate with increased analyzing frequency.
Another task to which the invention is directed is the provision of data in the form of measured values that can be documented. Moreover, the output data should be correlated to a scale related, for example, to normal or pathological concentrations. Furthermore, it is advantageous to design the apparatus in such a way that a clear correlation of sample and documented data can be carried out easily and without error.